The present invention relates to an improved monitor stand assembly, and more particularly, to an adjustable monitor stand assembly having structural features to prevent an upper stand portion from dislocating or separating from a stand base portion due to application of an increasing turning force during rotation of the monitor. The monitor stand assembly of the present invention also includes features for readily controlling the angle of rotation of the monitor by providing improved structural configurations of both the upper stand portion onto which a monitor is mounted, and the stand base portion which allows the monitor to rotate in a limited arc angle in both the up-and-down tilt direction and the right-to-left direction.
Generally, a monitor adopted in office automation equipment displays data on its screen to facilitate manipulation of the data by the user. A monitor stand assembly is provided for adjustably moving the monitor in both the up-and-down tilt direction and the right-to-left direction to allow a user to fix the monitor in a proper viewing position. In practical use of such a monitor stand assembly, the turning radius of a monitor is controlled within a limited angle range, and coupling and detaching of the monitor is also to be achieved with a simplified assembly process.
As illustrated in FIGS. 1-4, an example of a conventional monitor stand assembly is provided with an upper stand portion 11 integrally formed with cabinet 10 which houses and shields various electric components and a cathode ray tube (CRT) (not shown). A driving portion 12 is generally centered on upper stand portion 11 and has a spherical surface, concave on top and correspondingly convex on its bottom, to enable positioning of the monitor (not illustrated) by tilting up or down. Driving portion 12 mainly refers to the convex underside of upper stand portion 11. A guide slot 12a is provided through driving portion 12 for controlling the angle of tilt-rotation of upper stand portion 11. At one end of guide slot 12a, a resilient tab 13 of a predetermined elasticity is formed by a pair of slits 13a in upper stand portion 11. Resilient tab 13 thus has one end securely fixed to and integrally formed on upper stand portion 11, and a flexible free end which constitutes one end of guide slot 12a. On the top surface of resilient tab 13 is mounted a reinforcing boss 14 which can move resilient tab 13 up and down so as to allow upper stand 11 portion to be attached more easily to a stand base portion 20. On the bottom surface of resilient tab 13 is protrudently formed a direction controlling pin 15 for controlling the rotation of the monitor from right to left.
A pedestal-like stand base portion 20 is provided in combination with upper stand portion 11, on which a circumferential periphery contact portion 20a is formed. Contact portion 20a is generally circular and defines within it a generally concave surface to matingly engage with the bottom surface of driving portion 12 to slidingly enable upper stand portion 11 to rotate from right to left and tilt up and down thereon.
A fixing bar 21 is protrudently formed at substantially the center of stand base portion 20. Fixing bar 21 is disposed to be inserted into guide slot 12a to securely fix upper stand portion 11 onto stand base portion 20. Beside fixing bar 21, a direction controlling aperture 22 is formed in stand base portion 20 into which direction controlling pin 15 is inserted enabling rotation of the monitor in the right to left direction by a user in order to manipulate it to a proper viewing position.
On the bottom surface of stand base portion 20, a control rib 23 is protrudently formed which provides contact surfaces to direction controlling pin 15 for controlling the angular range of right to left rotational motion of the monitor. One portion of control rib 23 is comprised of a vertical plane or wall, while another portion is comprised of a slope with a predetermined angle of inclination.
The components of monitor stand assembly described above are depicted in cross-section in FIG. 4 in their assembled configuration: with upper stand portion 11 rotated approximately 90.degree. clockwise relative to base portion 20 as shown in FIG. 1.
To assemble the monitor stand assembly, upper stand portion 11 and stand base portion 20 are first arranged to align with each other so that fixing bar 21 of base portion 20 is insertable into guide slot 12a of upper stand portion 11. Fixing bar 21 and guide slot 12a are then coupled to each other so that the spherical bottom surface of driving portion 12 of upper stand portion 11 engages contact portion 20a of stand base portion 20, and upper stand portion 11 is rotated an arc of predetermined degree so that upper stand portion 11 does not dislocate from the stand base portion 20.
Reinforcing boss 14 is moved in the direction of the arrow casing resilient tab 13 to move upwardly, and simultaneously direction controlling pin 15 is inserted into direction controlling aperture 22 and over the sloped portion of control rib 23. Once inserted, when the monitor is rotated in the lateral direction, controlling pin 15 bears against the vertical plane of control rib 23 to provide its rotational range. From a central orientation, the lateral movement of the monitor is limited by controlling pin 15 bearing against the vertical walls of control rib 23 at an angle approximately 45.degree. to the right and an angle approximately 45.degree. to the left. It can be seen that the rotational range of lateral, right-to-left, movement is thus approximately 90.degree.. The up-and-down tilt movement has a range of approximately 15.degree..
To disassemble the monitor stand assembly, upper stand portion 11 is detached from stand base portion 20 by pulling upwardly on reinforcing boss 14 of resilient tab 13, and simultaneously, in taking the reverse order of coupling upper stand portion 11, direction controlling pin 15 is removed from direction controlling aperture 22 of base stand portion 20 to achieve detachment of upper stand portion 11 from base stand portion 20.
In the configuration of the conventional type of monitor stand assembly as described above, an increasing moment caused by the force of rotating the monitor into a suitable position pushes the resilient tab upward at a right angle. This in turn causes the direction controlling pin to dislocate from the direction controlling aperture in the stand base portion, resulting in loss of control over monitor rotation and positioning.
In addition, breakage of the direction controlling pin in contacting the vertical plane of the control rib due to rotating the monitor disables the control structures and results in loss of effective control over monitor rotation.
Furthermore, it has been found that the upper stand portions of conventional monitor stand assemblies dislocate easily from their base portions thereby diminishing product reliability.